I find the tech specs of LITTELFUSE very informative,enlightening and reassuring.I am considering using them on my treasured reference level SPECTRAL electronics.Anyone with experience using or EE level comments? Many thanks. Music lover and long timeaudiophile, Peter.

Roger Modjeski of Music Reference only uses that brand of fuses in his amps & specs them very carefully for each model amp. Roger is quite outspoken about the perils of using "high end tuning fuses" & does not recommend them for his equipment.

Pretty sure Audio Magic uses LITTELFUSE as the basis for their aftermarket fuses, Super Fuse and Beeswax Fuse. Although if that’s true I imagine LITTELFUSE would probably not go along with the whole idea of filling the inside of the fuse with liquid or beeswax not to mention whatever else Audio Magic does to the fuse. And I suspect LITTELFUSE wouldn’t go along with cryogenic treatment of their fuses or even experimenting with fuse directionality. One can’t help wondering if LITTELFUSE even heard of wire directionality? Most likely not.

Peter, you’ve probably seen various references I’ve made to Littelfuse datasheets in the thread on SR fuses. And yes, Littelfuse is definitely to be commended for the very comprehensive, technically unimpeachable, and confidence inspiring information they provide on their fuses.

I have no doubt that Littelfuses of the same current ratings, voltage ratings, fast/slow ratings, and physical size as the ones in your equipment would provide proper protection, and would also not blow when they shouldn’t. As to how the resulting sonics would compare with either the stock fuses that are used in your components or with SR or other audiophile-oriented fuses, in the absence of reports from a variety of users who have performed careful, thorough, and unbiased direct comparisons in a variety of components and circuit applications (e.g., both AC mains fuses and DC rail fuses), I don’t think anyone can do more than speculate. And I think it can be expected that more often than not audiophile speculation will be in the direction of assuming that solid engineering and low price = inferior sonics.

I checked out the Littlefuse site and noticed that some, if not all, are lead free in their construction which is a must for audiophool fuses so they may just be the ticket for those who don't want to splurge on boutique makes. At the very least, it's a step in the right direction.

What Littlefuse should do is start pricing some fuses (maybe paint em or claim they're frozen or zapped with a mysterious proprietary mojo) at 74 times the normal retail, market to audiophiles with claims of instant improvement to all aspects of the sound of whatever it's installed in (add a ridiculously long "break in" time with an electron "directionality" imperative), get somebody to write an over-the-top complimentary post on this site, and sit back and wait for the cash drawer to fill. No audio geek worth their salt is going to spend any time doing the comprehensive comparison testing suggested by Al, and besides, isn't it better to "feel" improvements that aren't there than find out you've been overcharged for a 2 dollar fuse?

My BAT amp came with Littelfuse's for the output protection circuit. After a tube failed and blew the fuse, I replaced the tube and installed a new fuse from Radio Shack. The channels did not sound the same. I tried 2 other fuse brands and was not satisfied with the sound. I ordered fuses from Digi Key as Littelfuse was not available in my metro area. Definitely the best fuse for that amp in that position.

That's the only fuse I trust in my electronics (I am happier when they aren't fried -- they tend to sound better that way).

Also, for surge and fault protection: if your Spectral amps have crowbar fault protection, Littelfuse SCR's and diacs are there as a replacement. Unfortunately, they no longer make the PA series MOV's (Galco sells an equivalent).

All in all, solid company and solid engineering. I, for one, wouldn't be surprised if their engineers don't know about wire directionality. Whatever that means. In an AC system.

Since this thread is on the subject of fuses. My preamp uses a 1/2 amp 125 volt fast-blo fuse. I was told that I can use a 1/2 amp 250 volt fast-blo fuse as a replacement if needed. Is it safe to do this?

I don’t mean to cast aspersions on audiophile fuses, but in this particular area (safety & fire), I’m much more comfortable dealing with a company whose butt is on the line - providing protection for medical, aerospace and other industries where safety is paramount and the consequences of failure are high.

As such, my upcoming NiWatt amplifiers have specified both fuse holders and ceramic fuses manufactured by Littelfuse. Granted, ceramic may be overkill, but I don't put a price on safety ;-)

There are other good manufacturers, and again, I’m not debating the sonic benefits of an audiophile fuse (which raises the question: why no audiophile fuse holders?).

The way I look at it, if I can’t design a world class amplifier using standard fuses, then I should be in a different business.

Of course, people are free to experiment to their hearts’ content, and this is just my perspective as a manufacturer.

There is at least one audiophile fuse holder, a silver plated one from Acme Audio. I’m pretty sure your probably making A Strawman Argument wrt the safety issue since AFAIK there are no safety issues with audiophile fuses. If there were I kind of doubt they would be in business as long as they have. What is it, twenty years? Even the Acme fuse holder has been around like, forever.

Very likely, the audiophile fuses are reliable, but
I'm a bit OCD, and have extremely low risk tolerance ;-)

If I'm signing my name to something with safety implications, I'm much more comfortable with a manufacturer with track record in the medical industry (for example), where people can die as a result of a poor design.

For the same reasons, and in spite of the extraordinarily low probability of problems with glass fuses, I'm more comfortable with ceramic ones.

Thanks for the comments about Acme. I was unaware of them, and I'll check into it.

Many of the aftermarket fuses ARE ceramic. Can you believe it? If there were any failures of aftermarket fuses I’m pretty sure you would hear about it here. And all over the Internet. But there is only the sound of crickets. One imagines you probably won’t be purchasing any liquid-filled audiophile fuses anytime real soon. ;-)

I certainly encourage consumers to use what makes them happy. I hope I made it clear - that my comments were the perspective as a manufacturer and nothing more.

I have a secondary reason for not specifying audiophile fuses, which is to not stack the deck. IOW, someone is free to experiment with replaceable parts to their heart’s content (as long as of course, they're consistent with the specification) and if they discover an improvement in their system, that’s great.

All too frequently however, people try to solve architectural (design) problems with band aids. This is not to diminish the importance of parts quality, and parts (whether it’s fuses or cables or anything else) is a topic for a whole ’nuther thread - a rabbit hole I don’t have time or inclination to rehash for the thousandth time ;-)

"All too frequently however, people try to solve architectural (design) problems with band aids. This is not to diminish the importance of parts quality, and parts (whether it’s fuses or cables or anything else) is a topic for a whole ’nuther thread - a rabbit hole I don’t have time or inclination to rehash for the thousandth time ;-)"

Not sure I can agree that people are trying to solve architectural (design) problems, whatever that actually means, by replacing stock fuses with aftermarket fuses. It’s strictly a sound quality issue. Those audiophiles. What are you going to do?

I wasn't implying that an audiophile fuse was an attempt to fix an architectural design problem and I tried to make that clear in the last paragraph of my previous post:

All too frequently however, people try to solve architectural (design)
problems with band aids. This is not to diminish the importance of parts
quality, and parts (whether it’s fuses or cables or anything else)...

Here's an example of an architectural/design problem:

A poorly designed power supply regulation circuit that sends hash into the signal. The band aid fix? A cable with a rolled off top end to hide the problem. It's like turning up the volume on your car radio to mask the sound of your wheel bearing.

The real fix. A competent design. Fix the problem at the source.

A good cable (or fuse) is just that - a good component and I'm all in favor of that. What I'm lobbying for is to address as much as possible in the design of the product. I'd hope that you're on board with that concept.

The problem here is of course, what's a poor audiophile to do? Not everyone has design skills to identify the true source of the problem and as a result, they take a buckshot approach to solving it. I wish I could propose a solution to this conundrum.

Thom: As a multiple SET amplifier owner I applaud you in your efforts in bringing to market a new SET amplifier. My amplifiers are using 845, 45, and PX-25 output tubes. Each has a wonderful sound with it's chosen speaker.

Each has had a marked improvement in sonics when a Synergistic Research Black fuse was installed. I believe this is one of the best fuses currently available. I hope you will trial this fuse not as a manufacturer but as an inquisitive audiophile. I am certain you wear both hats- manufacturer and audiophile. For many reasons as a manufacturer the Black fuse may not be an option, but please do not deny the music lover within you the chance to hear your product with one of the best sounding fuses available.

What makes this decision simple to me is they are offered with a 30 day trial and full refund. You would also being doing your customers a service by being able to convey to them your impression of what this fuse does or does not do.

To ebm. Caps in heading were inadvertent. I was in a hurry. I tried to correct it later but system wouldn't allow it after the 1st post. Correction allowed only before someone else posts. Fwiw, I do think it's an important topic and was impressed to learn the LITTELFUSES are used in critical medical and aerospace industries. I am not commenting on sound quality as I haven't tried them--but I will report after I try them ( I'm trying to rationalize a purchase based on the age of the 'old' fuses in use;but,it seams I have heard somewhere that the longer the metal is in use the smoother the current flow? ). I did take a look at one of the 'audiophile quality' manufacturers mentioned in a post above. Honestly; I found the information ludicrous,or silly. My guess is there must be truly ocd types in this hobby that will buy "anything" to satisfy there craving - and P.T. Barnum made it official years ago that a fool and his money are soon parted

At the risk of getting flamed by one particular fellow whose panties get quite wadded at the mention of Roger Modjeski’s name (apparently for not believing in the audible superiority of all audiophile boutique parts.), here’s what Roger found when he opened one of the eight Hi-Fi Tuning Fuses that were in one of his RM9 amplifiers returned to him for repair after the fuses had not done what a fuse is supposed to do when presented with a short: blow.

Roger discovered that the fuse was not designed for, capable of, or suitable for, use in a DC circuit---the very kind of circuit in which a tube operates. The customer’s RM9 had a tube fail, and the Littlefuse Roger installs in his amps would have done what a fuse is supposed to do when faced with a short in the DC circuit of a tube amp---blow. The Hi-Fi Tuning fuse did not, and the amplifier was then of course damaged. Not as a result of a fault in the design of the amp (unless you don’t want your tubes fused---Audio Research amps aren’t, ARC instead letting a resistor blow when a tube goes bad, thus requiring the resistor and any related parts to be replaced, rather than a fuse. At far higher cost, of course.), but because those fuses do not possess "high breaking capacity".

Surprised, Roger called first the U.S. distributor of the Hi-Fi Tuning Fuses, then the German designer/manufacturer. To his astonishment, neither knew what the term "high breaking capacity" means. That’s right---a fuse "designer" who knows less about fuses and their construction than an amplifier designer/manufacturer! The moral of this story is, if you are going to spend more on a fuse than a tube (if that doesn’t give you pause, spend on ;-), you might want to make sure the fuse is up to the task it is asked to perform in whatever application it is employed.

As an audiophile, I'm interested in the fuses. In retrospect, I could have made this a bit more clear.

The fuse argument is much like the power cord argument. People contend that inexpensive wire is in your walls, so why would the last 6 feet matter, and yet most people reading this will agree that it does.

As a manufacturer, an owners' manual is of course a legal document which is why we find those silly opening instructions - don't stand in a bathtub full of water while operating, etc.

I like the idea of furnishing a solid design with good parts, while leaving a bit of untapped potential for the end user to discover (better tubes, and fuses).

Thom and Bdp24, thanks for providing those inputs and perspectives. For those who may be interested in the meaning of "breaking capacity," also known as "interrupting rating," those terms are defined on pages 6 and 7 (pdf pages 10 and 11) of the following Littelfuse document:

Just curious, does LITTELFUSE also have a PDF file that discusses the directionality of fuses or wire generally? Maybe they just haven’t caught up to the aftermarket guys. Wire directionality is an important ingredient of fuses as we have seen. Is it possible high end audio is ahead of mainstream companies? Like with the Grapheme and the quantum dots.

Geoff, searching for the terms "direction," "directional," and "directionality" in the 294 page fuse catalog/design guide I linked to above, as well as in the search box provided at the Littelfuse home page, returns nothing that is relevant to your question.

Thanks for looking, Al. I'm not really surprised. But where can one go to read up on wire directionality? MIT? Georgia Tech? Maybe NASA has a technical paper on line, or even AES. Darpa? Belden Cable? Most likely fuse and wire directionality will have to be audiophile's little secret.

The fuse argument is much like the power cord argument. People contend
that inexpensive wire is in your walls, so why would the last 6 feet
matter, and yet most people reading this will agree that it does.

Thom, its not hard to measure the effects of the power cord. The measurements seem to correlate with listening experience (on an amplifier, measure the voltage drop across the cord and also measure the power output; compare to the power output of the amp if the voltage is corrected at the IEC connection using a variac).

We've seen a 2 volt drop across some power cords, which with some of our amplifiers results in a loss of 40 watts. Pretty significant and not a measurement 'buried in the noise'.

You can also measure the effects of a fuse, however we've not been able to measure any effects of the boutique fuses as being any different than the regular ones, assuming that they were indeed the right rating. All that I've ever used is a regular 3 1/2 digit DVM.

If you could use the wiring in the walls as a power cord it would work quite well. However such use is illegal and dangerous due to the wire being solid core.

"You can also measure the effects of a fuse, however we’ve not been able to measure any effects of the boutique fuses as being any different than the regular ones, assuming that they were indeed the right rating. All that I’ve ever used is a regular 3 1/2 digit DVM."

When you say "we've not been able to measure any effects of the boutique fuses..." you’re probably not referring to HiFi Tuning, you know, that squirrely aftermarket fuse company that published third party fuse measurements on their web site. They measured some of the various HIFi Tuning fuses, other fuses, including stock off the shelf fuses, in both directions and cryo'd and in cryo'd.

Geoffkait: I've never been able to navigate HiFiTuning's website, even using Google Translate on Chrome. Perhaps you could post a direct link?

Ralph: With respect to power cords, I suspect that a lot more is going on than resistance/voltage drop. If we had the time to play with this, I suspect we'd find inductance, capacitance and shielding would play as significant (if not more) of a role as resistance.

I've done the solid core, household wiring power cord experiment, and the results weren't all that good. It might be worth repeating this one, however.

Nonoise, thanks for providing the link. As some here will recall, the HiFi Tuning measurements were discussed extensively several years ago in the very lengthy "Fuses That Matter" thread. I provided comments on those measurements in a number of posts in that thread, most notably in my post about 3/4 of the way down on this page, dated 5-14-2012, 11:24 am EDT.

Thom, in addition to his comments above about power cord resistance/voltage drop, in a number of past threads Ralph has also emphasized that a power cord should provide bandwidth extending up into the tens of kHz, especially in the case of power amplifiers (since as I’m sure you realize their current draw typically consists of narrow spikes of high amplitude during a relatively small fraction of the 60 Hz cycle). And as you mentioned shielding also figures to be a significant factor in many cases.

I would add, though, that low resistance and hence low voltage drop, wide bandwidth, and good shielding in a power cord can be obtained at much less than kilobuck prices.

Regards,-- Al

P.S: BTW, Thom, I like your taste in speakers :-) (Mine are Daedalus Ulysses, which when I was last aware were your reference speakers).

Al, Thanks for providing the link to the HiFi Tuning data discussion of yore and thanks to no noise for the link to the data sheets. I went back and read the page of the discussion of the HiFi Tuning data this morning and was surprised to see it had been discussed to such an extent here. Even with all that has happened in the interim, you know, with the Red Fuse, the Black fuse, the Audio Magic Super Fuse and so forth, the skeptics are still holding their position. Looks like were not going to be able to take the Ant Hill.

At
the risk of getting flamed by one particular fellow whose panties get
quite wadded at the mention of Roger Modjeski’s name (apparently for not
believing in the audible superiority of all audiophile boutique
parts.), here’s what Roger found ...

If the power cord does not have a voltage drop, has good shielding and also good high frequency characteristics, its sound quality will be as good as a much more expensive cord with the same characteristics.

Power cords are not actually voodoo, but there is a surprisingly large and totally unnecessary snake oil. I suspect this is because many of the power cord manufacturers simply don't know why their cable works.

Its hard to sell products for top dollar that are advertised to work just like all the other good ones.

Is there anyone who really believes that high end audio manufacturers are so noble as to not do whatever they can to stand out from the crowd and try to maximize sales and profits, just like everyone else? After all, it "sounds better". We should just be more trusting and less skeptical. So funny!

As you appear to be implying, the answer is "of course not." Sometimes "better" specs can even be an indication that the component will sound worse, because they indicate a misplaced priority in the design. But a more expensive component doesn't necessarily sound better than a less expensive component, either. And that is particularly true when it comes to cables and power cords, IMO. As you've probably seen, the degree of correlation between cable price and cable performance has been discussed in many prior threads, such as this one.

An excerpt from one of my posts in that thread, which relates to the point Ralph made just above:

It seems to be generally agreed by most audiophiles that cable
performance cannot be either fully explained or fully predicted based on
generally recognized science. It follows from that, however, that the
cable designers have no way to accurately predict the point of
demarcation between optimization of a given cable parameter or design
characteristic and what may be overkill of that parameter or design
characteristic, which will accomplish nothing in most or all
applications. Therefore it can be expected that what is likely to be a
significant driver of the cost of many very expensive cables is overkill
of some or all of their design parameters and characteristics, which
will accomplish nothing in most or all applications.

One thing I’ll say about some products like, Atmasphere for example, having read about and actually heard them is they do take a somewhat unique approach (OTL tube amps) that is understandable in regards to how things work and why different and there are rules one can follow to help make sure things sound excellent when integrated and set up right. Or not

That’s much different than products that may appear unique but rational explanations regarding how they sound different or better are elusive. There are few reliable rules one can follow. Fuses and wires come to mind.

But look in the end its all about marketing and whether or not customers are happy or not. if someone thinks they hear something different or better facts really do not matter much. Except maybe to someone else. Paying more usually only helps with this. Silly humans!

If the power cord does not have a voltage drop, has good shielding and also good high frequency characteristics, its sound quality will be as good as a much more expensive cord with the same characteristics.

Power cords are not actually voodoo, but there is a surprisingly large and totally unnecessary snake oil. I suspect this is because many of the power cord manufacturers simply don't know why their cable works.

When can we expect Atma-Sphere PCs? Probably better margin than amps and preamps?

The pony I like is good engineering. It’s funny how the best engineers think alike about a lot of things, and respect each other’s work. For instance, Ralph Karsten (the atmasphere posting here, as most I’m sure already know), Mike Sanders, Tim de Paravicini, and, yes, Roger Modjeski ;-), to name but a few. As Ralph just pointed out in the thread on fuse directionality, knowing that a fuse in an AC circuit cannot, by definition, be directional is about as basic as electrical engineering gets, for gosh sakes.

bdp241,033 posts04-06-2016 2:04pmThe
pony I like is good engineering. It’s funny how the best engineers
think alike about a lot of things, and respect each other’s work. For
instance, Ralph Karsten (the atmasphere posting here, as most I’m sure
already know), Mike Sanders, and, yes, Roger Modjeski ;-), to name but a
few. As Ralph just pointed out in the thread on fuse directionality,
knowing that a fuse in an AC circuit cannot, by definition, be
directional is about as basic as electrical engineering gets, for gosh
sakes.

Audiophile fuses have been in the market for YEARS and if they are not designed for ,capable of, or suitable for, use in a DC circuit---the very kind of circuit in which a tube operates ... why is the market growing and these voodoo companies are not out of business? Give me ANOTHER LEGITIMATE case, except for the ONE pony, where it damaged a component?

I hate to burst everybody’s bubble. Not only are all fuses directional but all wire is directional, at least the ones with metal conductors. It’s not like this is exactly headline news, which makes this so difficult. Every Yutz with ears has know this for at least twenty five years. Have you guys been living in a cave or something? You can come out, now. The war has been over for years. Bdp24, you're following the wrong sheep.

Whether or not wire is directional is a separate matter from the directionality of fuses. Directionality of a fuse, in an AC circuit? AC, short for Alternating Current. That term is quite literal, and has explicate implications. We all agree Ralph knows what he’s talking about, right?

"Whether or not wire is directional is a separate matter from the directionality of fuses. Directionality of a fuse, in an AC circuit? AC, short for Alternating Current. That term is quite literal, and has explicate implications. We all agree Ralph knows what he’s talking about, right?"